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Henderson Island

Henderson Island

Henderson Island, which lies in the eastern South Pacific, is one of the few atolls in the world whose ecology has been practically untouched by a human presence. Its isolated location provides the ideal context for studying the dynamics of insular evolution and natural selection. It is particularly notable for the 10 plants and four land birds that are endemic to the island.

Outstanding Universal Value

Brief synthesis

Henderson Island is a remote and uninhabited elevated coral atoll located in the eastern South Pacific. It is the largest of the four islands of the Pitcairn Island group of which only Pitcairn, lying 200 km to its southwest, is inhabited. Covering some 3,700 ha but unsuitable for agriculture and with little fresh water, the island has no major land mass within a 5,000 km radius.

This gem in the middle of the Pacific is one of the world's best remaining examples of an elevated coral atoll ecosystem. It exhibits remarkable biological diversity given the island’s size, with four endemic species of land birds, ten taxa of endemic vascular plants and large breeding seabird colonies. It is of Outstanding Universal Value due to the comparatively low level of disturbance which provides a key for baseline information on similar atolls, and its isolation makes it ideal for studying the dynamics of island evolution and natural selection.

Criterion (vii): As one of the last near-pristine limestone islands of significant size in the world, Henderson Island retains its exceptional natural beauty with its white, sandy beaches, limestone cliffs, and rich and almost undisturbed vegetation. With its vast numbers of breeding seabirds, the island is an outstanding example of a raised and forested oceanic coral atoll with its fundamental features intact.

Criterion (x): While isolated coral atolls are typically species-poor, all four of Henderson’s land birds are endemic including the very distinct flightless Henderson Crake. At least four other endemic and one native species of bird are believed to have become extinct following human colonization. The island today is the only known breeding site of the endangered Henderson Petrel and is an important breeding area for at least ten other seabird species. While the flora is also typically poor with some 57 native vascular species recorded, these include six endemic species, three endemic varieties and another species endemic to Henderson and Pitcairn. As the island has never been intensively studied it seems likely that other as yet unidentified endemics occur. For example, the island's invertebrate fauna is little known but about one-third of the insects and gastropods so far collected are endemic.

Integrity

Henderson was colonised by Polynesians between the 12th and 15th centuries, but since then the island has remained uninhabited. The inhospitable nature of the island, together with its remoteness and inaccessibility, has so far effectively ensured its conservation. As a near-pristine island ecosystem, it is of immense value for science.

The conditions for integrity are largely met except the need for strengthening the legal status and the implementation of the management plan. Invasive alien species pose the greatest threat to the property. Polynesian Rats, introduced some centuries ago, have been shown to deplete native bird populations. The challenge of preventing new introductions, especially as the island is unguarded and tourists as well as fishermen regularly land on the island, are one of the greatest threats to the continued integrity of the property. Marine pollution with large amounts of plastic debris washed up on the beaches also detracts from the outstanding beauty of the property.

Protection and management requirements

Henderson Island is Crown Land within the Pitcairn Islands group, an Overseas Territory of the United Kingdom. It is subject to the Lands Court Ordinance (Revised Edition of the Laws 2001), Part VII of which gives to the Governor responsibility for possession, occupation, and transference of the lands of the islands. The Wellington-based British High Commissioner to New Zealand holds the office of Governor of Pitcairn.

While the Governor holds most formal powers, much day-to-day administration of the islands’ affairs is devolved to a Commissioner based at the Pitcairn Islands Administration office in Auckland. The Island Council, comprising a Mayor, Secretary, the Chairman of the Internal Affairs Committee, four elected officials, and two appointed advisers, is responsible for the local government and administration of internal affairs within the Pitcairn Islands, including decisions on when to visit any of the other islands in the Pitcairn group. There is also a Conservation and Quarantine Officer whose remit includes Henderson Island. Access to Henderson requires a licence issued by the Governor (through the Pitcairn Island Administration office) in consultation with the Island Council. The local population on Pitcairn includes some 58 inhabitants, making pressure on Henderson Island, located 200 km to its northeast, low. However, visitors from yachts and fishing vessels may arrive to Henderson before arriving at Pitcairn and not know that access is by permit only.

The Henderson Island Management Plan outlines a number of management goals with the principle of working with the Pitcairn Islanders to ensure on-site protection, and to review the legal status of the island with consideration for upgrading it to a Nature Reserve. Specific goals are to ensure that the biological, geological, and archaeological values are conserved, and that stocks of two timber species (Miro Thespesia populnea and Tou Cordia subcordata, both introduced species) are adequate to meet the needs of Pitcairners on a sustainable basis. An ambitious Polynesian Rat eradication programme has been initiated, and measures are being put into place to ensure that no new introductions of alien invasive species occur through regulated tourism. An awareness programme, involving education and research, forms part of this plan.

A number of international conventions relevant to nature conservation and environmental protection have been extended to the Pitcairn Islands. In short, these include the Ramsar Convention on Wetlands; the CITES Convention on Endangered Species in International Trade; the World Heritage Convention; the Bonn Convention on Migratory Species; the Vienna Convention on Substances that Deplete the Ozone Layer; the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter; and the Convention for the Protection of the Environment of the South Pacific Region (SPREP).